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8/27/2014 12:48 A.M. ET

Pomeranz prepared for pivotal start in Houston

HOUSTON -- Lefty Drew Pomeranz will return to the A's rotation for the first time since June 16 on Wednesday in a start against the Astros that could very well dictate where he pitches next.

Although a good performance doesn't guarantee Pomeranz sticks on the roster, it can only help his chances of being a prominent September contributor when rosters expand on Monday. Whether that's in the rotation or bullpen is unknown.

"We'll take it day to day on this one, see how [Pomeranz] pitches tomorrow," said manager Bob Melvin, "and then we'll make our decision accordingly."

"I know I'm pitching tomorrow and that I want to win tomorrow, and whatever happens from there is whatever happens," Pomeranz said. "It's not worth me thinking about it."

Pomeranz could potentially supplant Jason Hammel in the rotation at some point, though Hammel proved his worth in Tuesday's 4-2 loss with a one-run, seven-inning outing in Houston. Still, he has a 5.77 ERA in eight starts for the A's, who acquired his services with Jeff Samardzija in a July deal with the Cubs.

Their arrival prompted the A's to keep Pomeranz in Triple-A after his rehab from a broken right hand, which he sustained while punching a wooden chair, even though he had given them a 3.21 ERA in eight starts.

"We talk often about the 25-man roster and then maybe 30-plus guys that you really feel like are part of your team, and he's definitely one of those guys," Melvin said. "He's really been important to us, whether it was a starting role or in relief. He's done a nice job for us. Just because of the trades we made is the only reason he got pushed out."

Pomeranz kept pace with the River Cats and focused on pitching deeper into games, posting a 3.69 ERA in eight starts. It was 2.88 before his last outing, in which he allowed six runs in 5 2/3 innings.

"I made a few bad pitches, walked a few guys and gave up some runs. It happens," said Pomeranz, fresh off a plane from Nashville, where the River Cats were playing. "I feel like I've been pitching pretty much the same. I feel good, same as I did before."

Lowrie, Punto nearing rehab stints for A's

HOUSTON -- A's shortstop Jed Lowrie played catch on Tuesday for the first time since going on the disabled list with a fractured right index finger, an encouraging sign that may mean he's close to a rehab assignment.

"Hopefully, if that goes well, then maybe we speed things up with him," manager Bob Melvin said. "He's been doing everything he can to stay game-ready with taking ground balls. I know he's been doing some one-arm swinging in the cages. So today's a big day in how fast we move forward with him."

Lowrie is eligible to come off the DL on Thursday, but it seems more likely the A's will have him back sometime next week during a homestand that begins Monday.

Another rehabbing infielder, Nick Punto, is making equally significant improvement from a right hamstring strain, which has shelved him since the beginning of the month. He, too, could be sent out on a rehab stint soon.

"Everything's going well," Punto said Tuesday. "The running is that final step. Being able to go 100 percent, that's the key. I feel like I'm pretty close, maybe 90 percent. We're trying to take it day to day, not look too far ahead, but I do feel like I'm getting close."

"If we can take a few days with him and get him running to the point where we're comfortable with potentially getting in a game or two," said Melvin, "that's something we want to do sooner than later because the month's running out here pretty quick."

A's top two prospects lead group heading to AFL

HOUSTON -- The A's top two prospects as ranked by MLB.com, Daniel Robertson and Matt Olson, are among those who have been selected to participate in the Arizona Fall League.

The infielders will be joined on the Mesa Solar Sox by five other members of the A's organization, four of whom have been named: right-handers Drew Granier, Austin House and Tanner Peters; and outfielder Boog Powell.

The six-week league, which has established itself as the finishing school for the game's best prospects since its inception in 1992, begins its season Oct. 7.

Former A's prospect Addison Russell, traded to the Cubs for Jeff Samardzija and Jason Hammel in July, has also been named to the Solar Sox roster. He wasn't the only quality shortstop the A's landed in the 2012 Draft, though.

With the club's second choice, at No. 34 overall, Oakland selected Robertson and signed him for $1.5 million. The 20-year-old is having an outstanding season at Class A Advanced Stockton, batting .312/.404/.475 with 15 home runs and 58 RBIs in 127 games.

Olson came to the A's in the same Draft in the compensation round. The No. 47 overall pick has played mostly first base for Stockton, showcasing an abundance of power with 36 home runs in 486 at-bats. Overall, he's hitting .255 with a .937 OPS.

Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.